def f(arr):
    n=len(arr)
    if n==0:
        return None
    if n==1:
        return 0
    if n==2:
        if arr[0]<arr[1]:
            return 1
        if arr[0]>arr[1]:
            return 0
        return None
    for i in range(1,n-1):
        if arr[i]>arr[i-1] and arr[i]>arr[i+1]:
            return i
    return None
arr=[1,4,3,2,5,1]
print(f(arr))
s='I like python'
one=s.find('a')
print(one)
two=s.index('a')
print(two)